Please acknowledge the following before installing JFS:
- JFS patch should be properly applied to your JIRA Jira instance; patching is mandatory; patches are distributed as separate ZIP files at the Downloads
- You must restart your JIRA Jira immediately in case of any change made to JFS state via UPM (aka 'Manage Add-onsapps'). This includes installing, enabling, disabling, upgrading, uninstalling etc. of JFS add-onaddon.
- You also must restart JIRA immediately if you update UPM add-onaddon. Updating UPM causes reloading (i.e. disabling then enabling) of all user-installed pluginsapps, including JFS, which in turn requires JIRA restart.